package com.kaibes.im.utils;

import android.annotation.SuppressLint;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class EncryptUtil {
    private final static String ENCRYPTKEY = "0123456789";

    /**
     * 
     * @Title: getEncryptKey
     * @Description: 检验加密key
     * @param encryptKey
     * @return String
     * 
     */
    private static String getEncryptKey(String encryptKey) {
	if (null == encryptKey || "".equals(encryptKey))
	    return ENCRYPTKEY;
	return encryptKey;
    }

    /**
     * 
     * @Title: encrypt
     * @Description: 加密:普通java字串加密成16进制字串(String -> Byte -> HexStr)
     * @param content
     *            要加密处理的字串
     * @param encryptKey
     *            加密密钥
     * @return String
     * 
     */
    public static String encrypt(String content, String encryptKey) {
	byte[] encryptResult = encryptStrToByte(content,
		getEncryptKey(encryptKey));
	return parseByte2HexStr(encryptResult);
    }

    /**
     * 
     * @Title: decrypt
     * @Description: 加密:16进制字串解密成普通java字串(HexStr -> Byte ->String)
     * @param content
     *            要解密处理的16进制字串
     * @param encryptKey
     *            解密密钥
     * @return String
     * 
     */
    public static String decrypt(String content, String encryptKey) {
	byte[] decryptFrom = parseHexStr2Byte(content);
	byte[] decryptResult = decrypt(decryptFrom, getEncryptKey(encryptKey));
	return new String(decryptResult);
    }

    /**
     * 加密:字串 --> 二进制
     * 
     * @param content
     *            需要加密的内容
     * @param password
     *            加密密码
     * @return
     */
    @SuppressLint("TrulyRandom")
    private static byte[] encryptStrToByte(String content, String password) {
	try {
	    KeyGenerator kgen = KeyGenerator.getInstance("AES");
	    kgen.init(128, new SecureRandom(password.getBytes()));
	    SecretKey secretKey = kgen.generateKey();
	    byte[] enCodeFormat = secretKey.getEncoded();
	    SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
	    Cipher cipher = Cipher.getInstance("AES");// 创建密码器
	    byte[] byteContent = content.getBytes("utf-8");
	    cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
	    byte[] result = cipher.doFinal(byteContent);
	    return result; // 加密
	} catch (NoSuchAlgorithmException e) {
	    e.printStackTrace();
	} catch (NoSuchPaddingException e) {
	    e.printStackTrace();
	} catch (InvalidKeyException e) {
	    e.printStackTrace();
	} catch (UnsupportedEncodingException e) {
	    e.printStackTrace();
	} catch (IllegalBlockSizeException e) {
	    e.printStackTrace();
	} catch (BadPaddingException e) {
	    e.printStackTrace();
	}
	return null;
    }

    /**
     * 解密
     * 
     * @param content
     *            待解密内容
     * @param password
     *            解密密钥
     * @return
     */
    private static byte[] decrypt(byte[] content, String password) {
	try {
	    KeyGenerator kgen = KeyGenerator.getInstance("AES");
	    kgen.init(128, new SecureRandom(password.getBytes()));
	    SecretKey secretKey = kgen.generateKey();
	    byte[] enCodeFormat = secretKey.getEncoded();
	    SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
	    Cipher cipher = Cipher.getInstance("AES");// 创建密码器
	    cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
	    byte[] result = cipher.doFinal(content);
	    return result; // 加密
	} catch (NoSuchAlgorithmException e) {
	    e.printStackTrace();
	} catch (NoSuchPaddingException e) {
	    e.printStackTrace();
	} catch (InvalidKeyException e) {
	    e.printStackTrace();
	} catch (IllegalBlockSizeException e) {
	    e.printStackTrace();
	} catch (BadPaddingException e) {
	    e.printStackTrace();
	}
	return null;
    }

    /**
     * 将二进制转换成16进制
     * 
     * @param buf
     * @return
     */
    @SuppressLint("DefaultLocale")
    private static String parseByte2HexStr(byte buf[]) {
	StringBuffer sb = new StringBuffer();
	for (int i = 0; i < buf.length; i++) {
	    String hex = Integer.toHexString(buf[i] & 0xFF);
	    if (hex.length() == 1) {
		hex = '0' + hex;
	    }
	    sb.append(hex.toUpperCase());
	}
	return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     * 
     * @param hexStr
     * @return
     */
    private static byte[] parseHexStr2Byte(String hexStr) {
	if (hexStr.length() < 1)
	    return null;
	byte[] result = new byte[hexStr.length() / 2];
	for (int i = 0; i < hexStr.length() / 2; i++) {
	    int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
	    int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
		    16);
	    result[i] = (byte) (high * 16 + low);
	}
	return result;
    }

}